Background: Lymphomas that infiltrate the nervous system in children correspond to those of precursor B cells, such as lymphoblastic and Burkitt's lymphoma. In adults, infiltration occurs in mature B-cell lymphomas, such as mantle cell lymphoma, and, rarely, in Hodgkin's lymphoma or peripheral NK/T-cell lymphomas.
Case: We report the case of a 48-year-old man, who two years before death was diagnosed with extranodal nasal NK/T-cell lymphoma nasal in the left nostril. He received radiotherapy and a year later presented tumor activity. He also presented infiltration to the bone marrow and underwent chemotherapy. Afterward, he presented paresthesia and paresis of the lower extremities, difficulty walking, loss of sphincter control, and seizures. Infiltration to the central nervous system was revealed by computed axial tomography, and cytologic study of cerebrospinal fluid revealed malignant lymphoid cells; he then received intrathecal chemotherapy. He died 3 months later.
Conclusion: In Mexico, extranodal nasal NK/T-cell lymphoma occurs frequently. It is highly destructive and tightly related with the Epstein-Barr virus. Infiltration to the central nervous system is rare, and the neoplastic cells can be confused with other tumors, such as metastatic carcinomas.